scholarly journals Interfacial Compatibilization into PLA/Mg Composites for Improved In Vitro Bioactivity and Stem Cell Adhesion

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5944
Author(s):  
Meriam Ben Ben Abdeljawad ◽  
Xavier Carette ◽  
Chiara Argentati ◽  
Sabata Martino ◽  
Maurice-François Gonon ◽  
...  
Keyword(s):  
Diblock Copolymer ◽  
Interfacial Adhesion ◽  
Damping Factor ◽  
Biological Behaviour ◽  
Biological Studies ◽  
Full Study ◽  
Surface Localization ◽  
Poly Ethylene ◽  
Mechanical Performances

The present work highlights the crucial role of the interfacial compatibilization on the design of polylactic acid (PLA)/Magnesium (Mg) composites for bone regeneration applications. In this regard, an amphiphilic poly(ethylene oxide-b-L,L-lactide) diblock copolymer with predefined composition was synthesised and used as a new interface to provide physical interactions between the metallic filler and the biopolymer matrix. This strategy allowed (i) overcoming the PLA/Mg interfacial adhesion weakness and (ii) modulating the composite hydrophilicity, bioactivity and biological behaviour. First, a full study of the influence of the copolymer incorporation on the morphological, wettability, thermal, thermo-mechanical and mechanical properties of PLA/Mg was investigated. Subsequently, the bioactivity was assessed during an in vitro degradation in simulated body fluid (SBF). Finally, biological studies with stem cells were carried out. The results showed an increase of the interfacial adhesion by the formation of a new interphase between the hydrophobic PLA matrix and the hydrophilic Mg filler. This interface stabilization was confirmed by a decrease in the damping factor (tanδ) following the copolymer addition. The latter also proves the beneficial effect of the composite hydrophilicity by selective surface localization of the hydrophilic PEO leading to a significant increase in the protein adsorption. Furthermore, hydroxyapatite was formed in bulk after 8 weeks of immersion in the SBF, suggesting that the bioactivity will be noticeably improved by the addition of the diblock copolymer. This ceramic could react as a natural bonding junction between the designed implant and the fractured bone during osteoregeneration. On the other hand, a slight decrease of the composite mechanical performances was noted.

H2S-Donating trisulfide linkers confer unexpected biological behaviour to poly(ethylene glycol)–cholesteryl conjugates

2020 ◽  
Vol 8 (17) ◽  
pp. 3896-3907 ◽  
Author(s):  
Francesca Ercole ◽  
Yuhuan Li ◽  
Michael R. Whittaker ◽  
Thomas P. Davis ◽  
John F. Quinn
Keyword(s):  
Ethylene Glycol ◽  
Poly Ethylene Glycol ◽  
Biological Behaviour ◽  
Poly Ethylene

A comprehensive in vitro study into trisulfide-bearing PEG-conjugates was conducted. For these materials the combination of a cholesteryl group and an H2S donating moiety is required to confer cytoprotective and ROS-mitigating effects.

pH-responsive microspheres encapsulated with iron oxide nanoaggregates for gastrointestinal delivery

2012 ◽  
Vol 27 (1) ◽  
pp. 54-66 ◽  
Author(s):  
Young Ju Son ◽  
Hyuk Sang Yoo
Keyword(s):  
Iron Oxide ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Diblock Copolymer ◽  
Ph Responsive ◽  
Polymeric Microspheres ◽  
Intestinal Delivery ◽  
Poly Ethylene ◽  
The Stability

Block copolymer-stabilized iron oxide nanoaggregates were fabricated into pH-responsive polymeric microspheres for intestinal delivery of the magnetic nanoaggregates. A diblock copolymer consisted of methoxy poly(ethylene glycol) (mPEG) and poly(e-caprolactone) (PCL) was synthesized by ring-opening polymerization. Microspheres, consisted of Eudragit L100-55 encapsulate and stabilized magnetic nanoaggregates, were prepared by an oil-in-oil emulsification technique. The magnetization of the microspheres decreased, and the stability of the magnetic nanoaggregates in aqueous solutions increased as the amount of block copolymers in the microspheres increased. The encapsulated magnetic nanoaggregates were visualized by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The encapsulation efficiency of nanoaggregates of the microspheres increased as the amount of diblock copolymer in the nanoaggregates was increased. The in vitro experiments confirmed the pH-dependent release of the nanoaggregates from the microspheres. The microspheres were administered to the animals by oral gavages, and the nanoaggregates in small intestines were visualized by histological examination of intestinal inner walls. Higher amounts of the block copolymer in the nanoaggregates increased the uptake efficiency in the intestinal tissues. Thus, the incorporation of the block copolymers in the magnetic nanoaggregates increased the intestinal absorption of the aggregates and Eudragit microspheres and effectively protected the nanoaggregates at low pH conditions of the stomach area.

scholarly journals Well-Defined Diblock Poly(ethylene glycol)-b-Poly(ε-caprolactone)-Based Polymer-Drug Conjugate Micelles for pH-Responsive Delivery of Doxorubicin

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1510 ◽  
Author(s):  
Amin Jafari ◽  
Lingyue Yan ◽  
Mohamed Alaa Mohamed ◽  
Yun Wu ◽  
Chong Cheng
Keyword(s):  
Ethylene Glycol ◽  
Diblock Copolymer ◽  
Click Reaction ◽  
Ph Responsive ◽  
Poly Ethylene Glycol ◽  
Polymer Backbone ◽  
Drug Conjugate ◽  
Wide Range ◽  
Poly Ethylene

Nanoparticles have emerged as versatile carriers for various therapeutics and can potentially treat a wide range of diseases in an accurate and disease-specific manner. Polymeric biomaterials have gained tremendous attention over the past decades, owing to their tunable structure and properties. Aliphatic polyesters have appealing attributes, including biodegradability, non-toxicity, and the ability to incorporate functional groups within the polymer backbone. Such distinctive properties have rendered them as a class of highly promising biomaterials for various biomedical applications. In this article, well-defined alkyne-functionalized poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) diblock copolymer was synthesized and studied for pH-responsive delivery of doxorubicin (DOX). The alkyne-functionalized PEG-b-PCL diblock copolymer was prepared by the synthesis of an alkyne-functionalized ε-caprolactone (CL), followed by ring-opening polymerization (ROP) using PEG as the macroinitiator. The alkyne functionalities of PEG-b-PCL were modified through copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) click reaction to graft aldehyde (ALD) groups and obtain PEG-b-PCL-g-ALD. Subsequently, DOX was conjugated on PEG-b-PCL-g-ALD through the Schiff base reaction. The resulting PEG-b-PCL-g-DOX polymer-drug conjugate (PDC) self-assembled into a nano-sized micellar structure with facilitated DOX release in acidic pH due to the pH-responsive linkage. The nanostructures of PDC micelles were characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). In vitro studies of the PDC micelles, revealed their improved anticancer efficiency towards MCF-7 cells as compared to free DOX.

The effect of oxygenation on the biological behaviour of tumours

2007 ◽  
Vol 148 (30) ◽  
pp. 1415-1420 ◽  
Author(s):  
József Tóth
Keyword(s):  
Biological Behaviour

A rosszindulatú daganatokban gyakran ún. hypoxiás, csökkent oxigéntartalmú területek vannak (az oxigéntenzió < 7 Hgmm). A preklinikai, valamint klinikai vizsgálatok igazolták, hogy a hypoxia fokozza a tumorok progresszióját, agresszivitását. Szövettenyészeteken tanulmányozva az oxigén hatását, bebizonyosodott, hogy az oxigenizáció in vitro önmagában is gátolja az ép szövetek, a benignus és malignus tumorok sejtjeinek növekedését. Az onkoterápia szempontjából rendkívül fontos megállapítás, hogy ha egy daganatban az oxigén parciális nyomása kevesebb, mint 2,5 Hgmm, a sugárérzékenység lecsökken (intrinszik radiorezisztencia). Hypoxiás tumorokban számos kemoterápiás gyógyszer is hatástalan (kemorezisztencia). Oxigén hiányában vagy hypoxiás szövetekben a fotodinámiás kezelés is eredménytelennek bizonyult. Mindezen kísérleti és klinikai tapasztalatok alapján már évtizedek óta egyes intézetekben kiegészítő kezelésként, de egymagában is próbálkoznak a daganatos betegek oxigenizációjával. A leggyakoribb kezelési forma az oxigéngáz belélegeztetése (hiperbarikus oxigénterápia), vagy az oxigénnel telített víz alkalmazása fürdő vagy ivókúra formájában. A ma már nemzetközi kooperációban is végzett vizsgálatok egyértelműen igazolják az oxigénbevitel jótékony terápiás, radio- és kemoszenzitizáló hatását. Az általánosan alkalmazott eritropoietin-kezelés is bizonyítja az oxigenizáció jelentőségét a tumorterápiában. Időszerűnek látszik Magyarországon szakintézetekben nagy beteganyagon kivizsgálni az oxigenizáció tumorgátló, radio- és kemoszenzitizáló hatását.

scholarly journals Transcription of 4′-thioDNA templates to natural RNA in vitro and in mammalian cells

2015 ◽  
Vol 51 (37) ◽  
pp. 7887-7890 ◽  
Author(s):  
Hideto Maruyama ◽  
Kazuhiro Furukawa ◽  
Hiroyuki Kamiya ◽  
Noriaki Minakawa ◽  
Akira Matsuda
Keyword(s):  
Nucleic Acids ◽  
Mammalian Cells ◽  
Genetic Material ◽  
Rna Polymerases ◽  
Chemically Modified ◽  
Biological Studies ◽  
Modified Nucleic Acids

Synthetic chemically modified nucleic acids, which are compatible with DNA/RNA polymerases, have great potential as a genetic material for synthetic biological studies.

scholarly journals A modular microfluidic system based on a multilayered configuration to generate large-scale perfusable microvascular networks

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Tao Yue ◽  
Da Zhao ◽  
Duc T. T. Phan ◽  
Xiaolin Wang ◽  
Joshua Jonghyun Park ◽  
...  
Keyword(s):  
Large Scale ◽  
Circulatory System ◽  
Vertical Direction ◽  
Microfluidic System ◽  
Vital Role ◽  
Microvascular Networks ◽  
Biological Studies ◽  
Wide Range ◽  
High Flexibility

AbstractThe vascular network of the circulatory system plays a vital role in maintaining homeostasis in the human body. In this paper, a novel modular microfluidic system with a vertical two-layered configuration is developed to generate large-scale perfused microvascular networks in vitro. The two-layer polydimethylsiloxane (PDMS) configuration allows the tissue chambers and medium channels not only to be designed and fabricated independently but also to be aligned and bonded accordingly. This method can produce a modular microfluidic system that has high flexibility and scalability to design an integrated platform with multiple perfused vascularized tissues with high densities. The medium channel was designed with a rhombic shape and fabricated to be semiclosed to form a capillary burst valve in the vertical direction, serving as the interface between the medium channels and tissue chambers. Angiogenesis and anastomosis at the vertical interface were successfully achieved by using different combinations of tissue chambers and medium channels. Various large-scale microvascular networks were generated and quantified in terms of vessel length and density. Minimal leakage of the perfused 70-kDa FITC-dextran confirmed the lumenization of the microvascular networks and the formation of tight vertical interconnections between the microvascular networks and medium channels in different structural layers. This platform enables the culturing of interconnected, large-scale perfused vascularized tissue networks with high density and scalability for a wide range of multiorgan-on-a-chip applications, including basic biological studies and drug screening.

scholarly journals Effect of Gold Nanoparticles and Silicon on the Bioactivity and Antibacterial Properties of Hydroxyapatite/Chitosan/Tricalcium Phosphate-Based Biomicroconcretes

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3854
Author(s):  
Joanna Czechowska ◽  
Ewelina Cichoń ◽  
Anna Belcarz ◽  
Anna Ślósarczyk ◽  
Aneta Zima
Keyword(s):  
Gold Nanoparticles ◽  
Antibacterial Activity ◽  
Tricalcium Phosphate ◽  
Setting Time ◽  
Antibacterial Properties ◽  
Bone Substitutes ◽  
Bacterial Strains ◽  
Setting Times ◽  
Biological Studies

Bioactive, chemically bonded bone substitutes with antibacterial properties are highly recommended for medical applications. In this study, biomicroconcretes, composed of silicon modified (Si-αTCP) or non-modified α-tricalcium phosphate (αTCP), as well as hybrid hydroxyapatite/chitosan granules non-modified and modified with gold nanoparticles (AuNPs), were designed. The developed biomicroconcretes were supposed to combine the dual functions of antibacterial activity and bone defect repair. The chemical and phase composition, microstructure, setting times, mechanical strength, and in vitro bioactive potential of the composites were examined. Furthermore, on the basis of the American Association of Textile Chemists and Colorists test (AATCC 100), adapted for chemically bonded materials, the antibacterial activity of the biomicroconcretes against S. epidermidis, E. coli, and S. aureus was evaluated. All biomicroconcretes were surgically handy and revealed good adhesion between the hybrid granules and calcium phosphate-based matrix. Furthermore, they possessed acceptable setting times and mechanical properties. It has been stated that materials containing AuNPs set faster and possess a slightly higher compressive strength (3.4 ± 0.7 MPa). The modification of αTCP with silicon led to a favorable decrease of the final setting time to 10 min. Furthermore, it has been shown that materials modified with AuNPs and silicon possessed an enhanced bioactivity. The antibacterial properties of all of the developed biomicroconcretes against the tested bacterial strains due to the presence of both chitosan and Au were confirmed. The material modified simultaneously with AuNPs and silicon seems to be the most promising candidate for further biological studies.

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